duete; see due, ty 2 ]. syn: duty, obligation refer to something a person feels bound to do. A duty often applies to what a person performs in fulfillment of the permanent dictates of conscience, piety, right, or law: one's duty to tell the truth; a parent's duty to raise children properly.
Mutations in the RB1 gene are responsible for most cases of retinoblastoma. RB1 is a tumor suppressor gene, which means that it normally regulates cell growth and keeps cells from dividing too rapidly or in an uncontrolled way.
Retinoblastoma is a rare cancer originating in the part of the eye called the retina. The retina is a thin layer of nerve tissue that coats the back of the eye and enables the eye to see. Most cases (about 60 percent) involve only one eye (unilateral), but in some children, both eyes may be involved (bilateral). About 300 children are diagnosed with retinoblastoma in the United States each year.